GMA Comprehensive Practice Exam 2026 - Free Practice Questions and Study Guide

Epinephrine is indicated immediately when anaphylaxis is suspected. In a severe allergic reaction, it reverses the life-threatening parts of anaphylaxis—airway swelling and bronchoconstriction, plus low blood pressure from vascular leakage. Because delays can be fatal, it should be given right away, typically by intramuscular injection into the mid-outer thigh, even before all symptoms are fully confirmed.

Antihistamines and other medications can help with itching or hives, but they do not reverse airway compromise or hypotension quickly enough, so waiting to “try” them or delaying epinephrine is unsafe. Also, anaphylaxis can occur with more than just a skin rash, so you don’t wait for rash to appear before giving epinephrine.